Stock 440 rebuild: direction of piston

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bmxican

bmxican

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I have a quick question about a stock 440 rebuild (little mild) that I'm doing. I put the short block together and I realized something I didn't make note of: I didn't make note of which way pistons went into the block.

The top of the piston has two small dimples on the edge. I assembled the short block with all the dimples pointed towards the rear of the motor. Is this correct?

It's been like that in other motors I've worked on in the past. I'm hoping it's correct. It spins nice and freely and doesn't hit anything. I just want to double check. Thank you FABO! :D
 
On small blocks the notches go toward the front of the motor, I'm not sure what make pistons you have though and I've never built a big block. Are the oil squirt holes on the rods pointing towards the cam? I hope this helps.
 
I believe they all point forward.. But to be honest, a stock flat top with no reliefs should not have any offset to the pin. So it should be ok. But technically I think they face the front.
 
I put all mine in backwards I guess. Tomorrow I'll flip them over. Thanks for the help!

PS: These are flat top pistons, just stock.
 
i was told that puting them in back words will rase comp. 1pt. but you have to turn pis.onrod i was told this from an old class racer .if you look at the piston at the rist pin area you can see the offset. iv never done it my self .i think the next stock one i do will be done that way.
 
godfatherofchry said:
i was told that puting them in back words will rase comp. 1pt. but you have to turn pis.onrod i was told this from an old class racer .if you look at the piston at the rist pin area you can see the offset. iv never done it my self .i think the next stock one i do will be done that way.
Click to expand...


Interesting...
I do see the offset on the rod, I thought I had it right. Everything rotates nice and freely so I thought I was OK. I don't see how it wouldn't work but I just want to be safe and not ruin my motor.
Heading to school early to flip those over. See ya! :D
 
Turning them doesnt raise any compression. it simply is less friction when the piston is coming down. But manufacturers havent used offests in years because it meant having extra aprt numbers for a very small gain. And, as said, you have to dismount the rods from the pistons to turn them around and have the rods face the fillets properly. The rods only fit one way.
 
moper said:
Turning them doesnt raise any compression. it simply is less friction when the piston is coming down. But manufacturers havent used offests in years because it meant having extra aprt numbers for a very small gain. And, as said, you have to dismount the rods from the pistons to turn them around and have the rods face the fillets properly. The rods only fit one way.
Click to expand...

If the rods only fit one way, and I never removed the pistons from the rods, then that means I had them in the correct way, right? (with the marks facing the flywheel). If not, they wouldn't fit the other way (marks facing the timing cover), right?

Either way, I had time to remove the pistons and rods today, but I didn't have time to install them back on. I was too busy dealing with some retarded cam problems, which I'll save for another thread if I can't figure it out. Thanks!
 
The beveled edge on the big end of the rod always faces the crank. That keeps the bearing just a hair farther from the edge of the crank when installed. Does this make sense to you?
 
Robzilla said:
The beveled edge on the big end of the rod always faces the crank. That keeps the bearing just a hair farther from the edge of the crank when installed. Does this make sense to you?
Click to expand...

Look at the counter weight on the crank; see the bevel? your rods have a bevel on one side; they fit there. And the little hole in the bottom side of the rod squirts towards the cam.
 
bmxican said:
If the rods only fit one way, and I never removed the pistons from the rods, then that means I had them in the correct way, right? (with the marks facing the flywheel). If not, they wouldn't fit the other way (marks facing the timing cover), right?

Either way, I had time to remove the pistons and rods today, but I didn't have time to install them back on. I was too busy dealing with some retarded cam problems, which I'll save for another thread if I can't figure it out. Thanks!
Click to expand...

It means all the piston/rod assy you have on the even side(2,4,6,8)have to go on the odd side(1,3,5,7) and odds to even side. That way all the marks on the pistons face forward(like they should) and the rods fit together on the crank(bevels/fillets etc) like they should.Hope that helps?!
 
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